The upslope catchment (or simply contributing) areas represent the planar projection of the areas afferent to a point in the basin. Once the drainage directions have been defined, it is possible to calculate, for each site, the total drainage area afferent to it, indicated as TCA (Total Contributing Area).
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<h3>Inputs</h3>
<ul>      
<li>the file containing the matrix of drainage directions (obtained with Markoutlets or DrainDir, mflow})</li>
</ul>
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<h3>Output</h3>
<ul>      
<li>the file containing the matrix of the contributing areas (tca)</li> 
</ul>
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<h3>Notes</h3>
The values in the TCA output map are in number of pixels upstream, so they should be multiplied by the area of the pixels to have the area in km<sup>2</sup>.
